Grinders utilized for finish grinding the rod bearing journals of a crankshaft typically have a pair of spaced pot chucks for holding a crank shaft therebetween. The abrasive wheel of the grinder is positioned axially relative to one of the rod bearing journals for grinding of that particular rod bearing journal. During grinding both the abrasive wheel and the pot chucks rotate so that a smooth cylindrical surface may be obtained. To grind the next rod bearing journal the abrasive wheel is moved axially into alignment with the rod bearing journal to be machined and the rod bearing journal is indexed to the next desired location. Indexing of the crankshaft is achieved by a fixed gear set. Because the gear set is fixed, the indexing of the crankshaft is only applicable for the machining of a particular crankshaft configuration, for example, a crankshaft having four rod bearing journals.
To grind a crankshaft having a number of journals greater or less than the existing setup requires replacement of the existing gear set with a gearset having a different ratio. Thus, each crankshaft type requires a different gear ratio. For example, to grind a crank shaft with six rod bearing journals instead of four, a gear set capable of indexing the crankshaft to each of the six locations rather than four is required. Converting from one gear set to another requires several manhours of time in tear-down and setup. Making such a conversion is thus costly as it is manpower intensive and reduces overall productivity of the grinder.
Further, since the conversion from one crank shaft configuration to another is time consuming the flexibility of running small lots of crankshafts is eliminated. To alleviate this problem a separate grinder is often dedicated for each crankshaft configuration to be ground. This of course contributes to inefficiency and an increased cost of the crankshafts being produced.
In certain types of existing commercially available manual grinders the distance provided between the head and tail stock of the grinder is often less than necessary to permit the aforementioned indexible pot chucks to be used. This is due to the fact that the complicated indexing gear sets discussed above are massive and utilize much of the space available between the head and tail stocks. Thus, the remaining available space between the pot chucks is not adequate to permit a crank shaft to be supported therebetween.
Engines of today require that closer tolerances be maintained in the manufacture of various components, such as crank shafts, in order to meet operating specifications, such as particulate emission standards. Manually indexible grinders are difficult to adjust and difficult to hold tight tolerances with. Thus, increased scrap is produced which wastes resources but also drives up prices.
The present invention is directed to overcoming one or more of the problems as set forth above.